A search engine is a computer program that helps a user to locate information. Using a search engine, a user can enter one or more query terms and obtain a list of resources that contain or are associated with subject matter that matches those query terms. While search engines may be applied in a variety of contexts, search engines are especially useful for locating resources that are accessible through the Internet. One can use a search engine to generate a list of Universal Resource Locators (URLs) and/or Hypertext Markup Language (HTML) links to files, or pages, that are likely to be of interest. Such files, or pages, may be generally referred to as documents. Documents may contain text, images, and/or other data that is meaningful to humans or computers. For sake of simplicity, “document” is used herein to refer to a URL or HTML link to a file or page as well as the file or page itself.
Some search engines order a list of documents before presenting the list to a user. To order a list of documents, a search engine may assign a rank to each document in the list. When the list is sorted by rank, a document with a relatively higher rank may be placed closer to the head of the list than a document with a relatively lower rank. The user, when presented with the sorted list, sees the most highly ranked documents first. To aid the user in his search, a search engine may rank the documents according to relevance. Relevance is a measure of how closely the subject matter of the document matches query terms.
Because of the global nature of the Internet, a given set of query terms may cause a search engine to return a list that includes documents from multiple regions. Some of the documents, while having a high relevance with regard to the query terms, may contain subject matter that is primarily concerned with a region in which the user has no interest. For example, a user in France searching with a query term that contains “gouvernement,” the French word for “government,” may receive a list that contains documents that discuss the governments of the French-speaking provinces of Canada (because the documents contain the word “gouvemement”). If the user performed the search from a site in France, then the user may be surprised and dismayed that he is required to find, in a list that includes documents that discuss Canadian governments, documents that discuss the government of France. Even if the list contains documents that discuss the government of France, these may have a lower relevance rank, and may therefore be located lower in the list. Relevance rank alone often fails to compensate for regional differences.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.